In order to study the anti-projectile impact characteristics of the liquid-filled grid structure, the impact damage experiments of 1×1, 3×3 and 5×5 grid structures were carried out based on the two-stage air gun system. And some physical quantities such as projectile partial velocity and wall strain were obtained. Then the experimentally validated finite element model was established based on LS-DYNA finite element software. The physical quantities of the full-field variation of projectile velocity and wall deformation were obtained on the basis of experiments. The results show that the deformation of the rear panel is more serious than other panel, and the deformation of the lower half of the panel is larger than that of the upper half; and under the combined action of internal panel deformation and fluid flow on front panel, the deformation trend of front panel of 5×5 grid structure is different from that of 1×1 and 3×3 grid structure; the total energy obtained in the process of projectile impact increases with the increase of the number of grids, but the deformation of the inner panel dissipates more energy, which leads to the decrease of the deformation of the outer panel of the grids and improves the damage resistance of the structure.